Pusher dog for conveyer chains



Oct. 11, 1938. L. .1. BISHOP 2,132,455

I PUSHER DOG FOR GONVEYER CHAINS Filed May 14, 1936 2 Sheets-Sheet l :L l .i 1 6 Li /H ilm U '6 R825 7 3 450M450 J. 59%

ATTORNEY.

Oct. 11, 1938.

1.. J. BISHOP 2,132,455

PUSHER DOG FOR GONVEYER CHAINS Filed May 14, 1956 2 Sheets-sheaf, 2

INVENTOR. LEO/Vfl/PD J- fish OP Patented Oct. 11, 1938 PATENT OFFICE 7 2,132,455 PUSHE-R DOG FOR CONVEYER. CHAINS Leonard J. Bishop, Detroit, Mich., assignor to Mechanical Handling Systems, Inc., Detroit, Mich., a corporation of Michigan Application May 14, 1936, Serial No. 79,712

8 Claims.

This invention relates to conveyers and particularly to that general type known as floor con- Veyers as distinguished from overhead conveyers; floor conveyers being of the type wherein the articles to be transported are located above the conveyer chain. This type of conveyer requires some means projecting upwardly from the chain to contact the articles located above the chain to insure their propulsion alongthe line of travel. These projections are termed generally in the conveyer art as pusher dogs. As commonly used'the chain unit comprises an upper operating run and a lower return run, with sprockets at the ends of the runs and in certain cases at intermediate points along the line, channel guides also being provided for both the upper and lower runs. The pusher dogs must be so constructed as to automatically project upwardly in the upper run during operation and in the lower run preferably to be moved to an inoperative position so as to use as little space as possible during the return travel of the chain.

It is known in the art to employ a pusher dog pivoted upon one of the pins of the chain and having at one side of the pivot pin an upwardly projecting article engaging arm with a counter balance or tail portion extending from the oppo- 7 site side of the pivot and extending over and reacting against the next pin; this construction resulting in a unit of considerable length most of which projects above the chain proper.

It is a primary object of the present invention to provide a pusher dog of such construction that the counterbalanced portion will be in effect almost entirely housed within one link of the chain whereby not only decreasing the length of each dog and adding more weight to tail portion but also providing a more compact assembly with the chain and in addition securing a construction capable of being made from drop forgings without special machining operations. This construction eliminates the objectionable feature in some of the prior art structures wherein a standard link was required to be specially machined with considerable accuracy to provide for the addition of pusher dog parts.

It is the further object to provide a construction suchthat on the return travel of the chain, the pushers will fold closely to the chain and occupy a minimum of space and when so folded furnish a flat surface for supporting the chain for sliding movement on the adjacent guide surface.

It is the further object to confine the counterbalance or tail portion of the pusher in the central part of the chain and to adapt the same to operate between the links thereof so that interference which might otherwise result between the chain hold down means and the projecting portions of the pusher dog will not occur.

The above and other objects of the invention 5 will appear more fully from the following de-' tailed description of an illustrative embodiment of the principles of the invention and by reference to the accompanying drawings forming a part hereof and wherein:

Figure 1 is a side elevation partly in section showing an upper operating run of the chain and also a return travel run.

Figure 2 is a vertical section taken substantially on line 2--2 of Figure 1 and is an end view of the chain assembly showing the arrangement of the channel guide means therefor.

Figure 3 is a top view showing the general arrangement of the pusher dog and the special chain link.

Figure 4 is a section thru the chain and guide channels in a plane indicated by line t-4 of Figure 3 and shows particularly the counterbalance', the stop lug and its location relative to the adjacent pins of the chain. 25

Figure 5 is a section on the line 55 of Figure 1 and shows a transverse vertical section through the center of the chain link and shows the relative location of the pusher dog stop lugs.

Figure 6 is a section similar to Figure 4 but on a plane indicated by line 66 of Figure 3 and shows a side View of the pusher dog and its pivotal mounting together with its location relative to the other parts of the chain.

Figure 7 is a view similar to Figure 3 but showing a modified form of construction. Figure 8 is a section in line 88 of Figure 7.

Considering Figure 1, reference character I!) indicates an upper working run of a conveyer chain and H a lower return run thereof. At 4 some distance beyond the broken away sections there are provided sprockets, not shown, around which the chain travels. It is understood that suitable provision is made for driving the chain according to conventional practice with conveyers of the general type herein considered. According to general practice with this type of conveyer a guide is provided in which the chain operates. The guide assembly shown in Figure 2, however, has certain unique features which will be considered. Standard structural shapes are preferably used. to construct the guide assemblyand as shown in Figure 2 a channel l2 serves as a support for the upper or working run of the chain l0. Supported on the sides of the V matically indicated at 29.

channel l2 are angle hold down guides 53 and id which extend toward the center of the channel l2 leaving an open section l5 as shown. It is apparent that this construction results in a closed unit which defines a runway for the chain, the channel l2 retaining the bottom of the chain and the guides l3 and I4 retaining the top edges of the chain with an opening l5 along the longitudinal center. Below the upper guide assembly above described, there is provided a channel serving as a guide for the return run of the chain.

Considering Figures 1 and 3, a special link H is provided having side bars !8 which are fitted upon the ends of a bushing l8c which has noncircular ends lab which fitinto similarly shaped holes l8c in the side bars i8, the ends IBh preferably being either a tight press fit in the holes l8c or being slightly riveted over in assembling the parts to form a special link. When this special link is connected to adjacent standard links by pins I9, it is apparent that the two side bars l8 will be rigid with the bushing 18a. The side bars I8 are so shaped that a shoulder 25 is located centrally between the pins E9 on the inner surface of said bars, said shoulder being substantially U-shaped in side view as shown. The special chain link I! thus provides a unit easily assembled in place of a standard chain link, and affords a supporting shoulder midway between adjacent pins for a purpose which will presently appear.

The pusher dog forging 22 has a pusher portion 23 and a counterbalanced tail 24, said counterbalanced tail being provided with a laterally projecting lug 25 on each side thereof and also a downwardly projecting pivot portion 26 pro-- vided with an opening 2'1 which projection 26 fits between side bars 58 of chain link IT and forms a pivot with the right hand pin 19 as shown in Figures 1 and 3. The weight of the counterbalanced tail 24 is such that the pusher will normally assume the position shown in Figure 1 in which the upper end 23 is in position to contact an article to be pushed such as diagram The upward movement of the pusher around the pin. H? as a pivot is limited by the contact of the laterally projecting lugs 25 with the bottom of the U-shaped shoulders 20 in the side bars [8 of special link I1. The bottom of this shoulder also serves as. a reaction support for a portion of the load when a pusher is actually operating against an article to be conveyed.

It is noted that as each of the parts, i. e., side bars I8 and pusher dog 22, with the shoulders 20 on side bars l8 and the projections on the pusher dog 22, may be constructed of drop forgings within sufficiently close dimensions that it is not necessary to machine them after forging. This result is accomplished by the general arrangement of parts and particularly by the radius at the bottom of the shoulders 20 being made materially larger than the radius of the lugs 25. Ample clearance for movement of the dog from inoperative to operative position is thereby provided and a definite contact of the projecting lugs 25 against the shoulders is assured without resorting to accurately machined parts.

The operation of the device is as follows: Assuming the chain moving in the direction shown by the arrows in Figures 1 and 6, it will be understood that a plurality of pusher dogs 22 will be secured at spaced intervals along the chain. Be-

, causeof the heavier counterbalanced portions 24 of the pusher dogs 22, they will each automatically assume the position shown in full lines in Figure 6 ready to contact a load to be conveyed. The pusher dogs also are free to move to the dotted position shown in Figure 6 when a load is moved onto the conveyer as, for example, from the left to the right in Figure 6, the forward end first contacting the upwardly projecting arm of the pusher dog and folding it downwardly allowing article to pass over and when it reaches a position out of contact with the depressed arm of the pusher dog the weight of the counterbalanced tail 24 will cause the arm to assume the position shown by the full lines in Figure 6, that it, ready to push the load located at the right as shown.

Considering Figure 2, the construction of the pusher dog and chain is such that the supports of the pusher are substantially enclosed within a link of the chain and there are, therefore, no projections at the edges of the chain to interfere with hold down channels 13 and M. In other words, the grooved runway and guide for the chain can be made with a thickness substantially that of the chain without consideration of projections thereon and a more positive guide thereby obtained while an opening such as I5 at the central portion of the chain is sufiicient to allow for operation of the projecting arms 23 of the pusher dogs. This feature can be more readily appreciated when it is considered that some prior art devices have used counterbalanced tail portions which are entirely outside the chain and lie above the pins 19 using said pins as a reaction support. 7

As any portion of the chain travels with its pusher dog to the lower return travel run shown in the lower part of Figure 1, suitable guides at the turn cause the pusher dog to assume the position shown, that is, folded against the chain whereby the thickness or height of the chain and assembled dogs is merely the thickness of the chain plus a uniform thickness of the folded pusher dog member. It is noted that the pusher dog is of substantially rectangular shape in side View with counterbalanced tail 24 and pivot 26 projecting therefrom between side bars [8 of link ll. As shown in Figure 1, the pusher dog on the lower return run of the chain uses its substantially flat face as a sliding support for the chain on the lower channel Hi. This feature is considered an improvement over prior art devices which use only a small projecting portion to contact the guide. With the pusher in the folded position, the surface contacting the guide is substantially parallel with the chain and the plurality of spaced pusher dogs provided at spaced intervals on the chain serve as a substantial support during operation. 7

By referring to Figure 4, it will be noted that when the lugs 25 are in contact with the shoulders 20 of side bars IS, the reaction support thus formed is substantially on the same horizontal plane with, and midway between, two adjacent pins 19. The shape of the shoulders 20 is such that there is no interference when the lugs 25 swing in an are about pin l9 as a center and the radius at the bottom of each of said shoulders 20 is sufficiently larger than the radius of lugs 25 so that contact is made without binding at a point substantially at the bottom of said U- shaped shoulders. It is to be noted, furthermore, since the contact between the lugs 25 and shoulders 20 provided on the inner surface of the members l8 of the special link I! is midway between the adjacent pins l 9, that the load on the pusher dog tends to hold the chain fiat against the supporting channel 12 and obviates undue tendency toward objectionable buckling of the chain. This a tendency to buckle since the tail portion often extended even over the next link. In the present construction, the entire supporting system is con- 7 fined to one link and such compactness of design has obvious advantageous features in addition to those which have been pointed out above.

In the modified form of the invention in Figs. 7 .and 8 there is shown a somewhat simplified construction of straight side bar members with slots 3| preferably of arcuate shape, cut in the sides thereof for the purpose of limiting the travel of the dog; the lugs 25 projecting into said slots and the closed ends of the slots forming stops or shoulders against which the lugs abut to limit the travel of the dog. This type of side bar member has an advantage of simplicity in manufacture since such members can be constructed from standard stock by a stamping operation in place of a forging or casting as required in first described type.

Having specifically described my invention, I do not desire to confine myself to the specific details of the constructional example herein shown and described as it is apparent that various modifications may be resorted to without departing from the broad principles of the invention as indicated by the scope of the following claims.

I claim:

1. The combination with a conveyer chain having a series of pivotally connected transversely spaced side links, of a pusher member having a head, a counterbalance, and an intermediate pivot portion, said pivot portion being connected to the chain by one of the pivots connecting the links, said counterbalance extending into the space between said links, and projections on said counterbalance portion in the region thereof that extends between said links contacting said links.

2. In .a conveyer, a chain comprising links with vertical side members, shoulders on the inner surfaces of said side members, pivot pins connecting said links, a pusher member pivotally mounted on one of said pins and having a counterbalanced end, projections on said counterbalanced end for contacting said shoulders of said links.

3. The combination with a conveyer chain having one of its links provided with U-shaped shoulders with a radius at the bottom thereof, of a pusher dog pivotally mounted on said chain, counterbalance portions on said pusher dog, and projections on said counterbalance portions for contacting said shoulders, said projections being of circular cross section of a radius less than that at the bottom of said U-shaped shoulders thereby providing ample clearance for movement while affording a suitable reaction contact.

4. The combination with a conveyer chain having pin'connected links comprising pairs of side bar members with openingsv therebetween, of a pusher dog member comprising a pivot portion mounted on a pin connection of said chain, a

, pusher arm portion on one side of said pivot, a

stop in the opening between said-side bar members formed by the configuration of said members and a tail counterbalance portion on the opposite side of said pivot of such form and weight as to swing by gravity to a position limited by contact with said stop in the opening between the side bar members of said chain to hold said pusher arm portion in an operating position outside said chain. 5. In a conveyer system, a chain having pin connected links comprising pairs of side bar members, with openings therebetween, shoulders formed on said side bar members, a pusher comprising a pivot portion mounted on .a pin connection of said chain, a pusher arm portion on one side of said pivot, and a tail counterbalance portion on the opposite side of said pivot of such weight-and form as to swing in the opening between the side bar members of said chain to move said pusher arm portion to an operative position outwardly from said chain, and projecting lugs on said counterbalance tail for contacting said shoulders on said side bar members to form a support for said pusher dog in its operative position outwardly of said chain.

6. In a conveyer system, a chain having links with central openings therein, pin connections for said links, a shoulder formed in thecentral opening of a link of said chain, a pusher dog member, projections on said pusher dog member adapted to project into a central opening to contact cooperatively with said shoulder and an adjacent pin connection for a pair of said chain links to effect a support for said pusher dog on said chain.

7. In a conveyer having pusher dog members supported on a conveyer chain comprising pin connected centrally open links characterized by a projection on said pusher dog member forming a pivotal mounting on one of said pin connections, a stop in said open link adjacent said pivotal mounting, and a second projection on said pusher dog for contacting said stop.

8. In a conveyer system, .a chain having links With central openings therein, pin connections for said links, a supporting shoulder located within the central opening of a link of said chain substantially midway between adjacent pin connections of said link, a pusher dog member, a projection on said pusher dog member forming a pivotal mounting for said member on one of said adjacent pin connections of said links, a second projection on said pusher dog member for contacting said shoulder thereby to support said pusher dog centrally on said link.

LEONARD J. BISHOP. 

